QuestionLand‐use change and intensification are currently the most pervasive threats to tropical biodiversity. Yet, their effects on biodiversity change with elevation are unknown. Here, we examine how tree diversity and community composition vary with elevation and how the effects of forest use intensity on tree diversity and community composition change within elevations.LocationEastern slopes of the Cofre de Perote mountain, state of Veracruz, Mexico.MethodsWe assessed tree diversity and composition using a sampling design in which elevation was crossed with three levels of forest use intensity: old‐growth, degraded, and secondary forests. We established 120 20 m × 20 m forest plots, located at eight sites between 0 m and 3,545 m. At each site, five replicate plots were inventoried for each level of forest use intensity.ResultsOur analyses revealed an interactive effect between elevation and forest use intensity affecting tree diversity and community composition along the elevational gradient. Contrasting effects of forest use intensity within elevation resulted in tree diversity following a low‐plateau pattern for old‐growth and a bimodal pattern for degraded and secondary forests. Along the entire elevational gradient, there were 217 tree species distributed within 154 genera and 80 families. Species accumulation curves revealed that forests at 0 m and 1,500 m elevation showed differences in species richness among forest use intensities. In contrast, species richness did not differ between old‐growth forest and the other forest use intensities in five of the eight studied elevations. In terms of community composition, secondary forests differed from old‐growth and degraded forests.ConclusionOur results suggest that the interactive effects of elevation and forest use intensity change tree diversity patterns and community composition along a tropical elevational gradient. Degraded forests were similar to old‐growth forests in terms of species diversity and composition, suggesting that they may act as a safeguard of tree diversity in human‐dominated tropical landscapes.
The margay, Leopardus wiedii, and the ocelot, L. pardalis, are sympatric species through their distribution areas. Some studies indicate that L. pardalis exerts a strong influence on other smaller felids. Our goal in this study was to estimate the density and activity patterns of these felid species in two vegetation types at Sierra Norte of Oaxaca, southwestern Mexico. We expected that L. pardalis had a high density relative to other felids due to its ecological plasticity, as well as segregation in the activity pattern between species. We placed camera traps in 22 sites in the semi-evergreen forest and 22 sites in the cloud forest, from July 2014 to June 2015. We estimated density using the Cormack-Jolly-Seber probabilistic model with the program MARK and assessed the degree of activity overlapping between species by the coefficient of overlapping Δ 1 in the program R. We recorded low abundance of L. pardalis (8.3 individuals) and a higher abundance of L. wiedii (51.5 individuals). The density of both species was 7.8 individuals /100 km 2 and 81 individuals/100 km 2 , respectively. Both species displayed predominantly nocturnal activity. The overlap coefficient between species in the semi-evergreen forest was high (Δ 1 = 0.75, CI = 0.63-0.90). Factors such as differences in vegetation type and the presence of a large number of transient individuals may influence the density of Leopardus. The lower density of L. pardalis and the high conservation status of the cloud forest may contribute to the higher density of L. wiedii in Sierra Norte of Oaxaca. Our results suggested that both species showed a highly overlapping activity pattern, and the activity pattern of the margay is seemingly unaffected by the presence of the ocelot. We provided information about density and activity of medium-sized felids, as well as on the factors that may potentially affect these patterns in mountain tropical forests.El margay Leopardus wiedii y el ocelote L. pardalis son simpátricos a través de sus distribuciones. Algunos estudios indican que L. pardalis ejerce una influencia fuerte en otros felinos más pequeños. Nuestro objetivo fue estimar la densidad y el patrón de actividad de estos felinos en dos tipos de vegetación en la Sierra Norte de Oaxaca, en el Sureste de México. Esperábamos que L. pardalis presentara una densidad alta en comparación con otros félidos, debido a su plasticidad ecológica y también, esperábamos una segregación en el patrón de actividad entre especies. Ubicamos 22 sitios con trampas cámara en la selva mediana y 22 sitios en el bosque mesófilo de julio 2014 a junio 2015. Estimamos la densidad usando el modelo probabilístico de Cormack-Jolly-Seber con el programa MARK y evaluamos el grado de sobreposición de la actividad entre especies por medio del coeficiente de sobreposición Δ 1 en el programa R. Registramos una abundancia poblacional baja de L. pardalis (8.3 individuos) y una mayor de L. wiedii (51.5 individuos). La densidad poblacional de ambas especies fue 7.8 individuos/100 km 2 y 81 individuos/100 km 2...
Adaptations in species activity patterns allow animals to avoid risks generated by human activities and domestic and feral species. We aimed to evaluate the effect of anthropogenic activity on mammal activity patterns in two tropical ecosystems -semi-evergreen forest and cloud forest-, and its temporal variation in the Sierra Norte of Oaxaca, Mexico. We expected mammal activity patterns to show significant differences from activity patterns of humans and domestic species. From July 2014 to June 2015, we placed camera traps in 23 sites in a semi-evergreen forest and 23 sites in a cloud forest. We estimated the activity level of each species and calculated the activity overlap between wild species and humans and domestic species in each season. We recorded a total of 16 species of wild mammals, four domestic species, and obtained 738 human records. We found no evidence of an effect of anthropogenic activity on the activity patterns of wild mammals: we found similar activity levels between seasons and ecosystems, and moderate to high overlap between the activity patterns of some wild mammal species and of humans and domestic species. Low human population density, human activity temporal dynamics, and the plasticity of wild species could explain the results of our study.
Several species of neotropical felines are morphologically and ecologically similar, and are sympatric along large areas of their distribution. This requires mechanisms to allow their coexistence, such as temporal segregation of their activities. The aim of this study was to evaluate the relation between activity patterns of felines and their prey using camera trapping data and their seasonal variation in two tropical environments in south-western Mexico. Excepting Puma concolor, activity patterns for each feline species did not differ significantly between seasons nor between vegetation types. Activity patterns did not differ significantly between species of similar size: mid-sized species had high activity pattern overlaps in the medium forest while large-sized species overlapped to a lesser extent in the cloud forest. Leopardus wiedii differed from large-sized predators in its activity patterns. We recorded a relatively high temporal overlap between felines and their main prey species, particularly in the periods of maximum activity. We found no evidence of temporal segregation between the felines of the Sierra Norte region of Oaxaca and we suggest their coexistence is mediated by the selection of prey with different activity patterns.
Temporal niche partitioning between ecologically similar species may decrease interspecific competition and facilitate their coexistence, but the temporal interactions between sympatric skunks are still poorly understood. Furthermore, different interacting factors to explain activity patterns and their role in species coexistence in the temporal niche have been overlooked. Using camera traps over 2 years, we evaluated the temporal segregation between Conepatus leuconotus and Spilogale pygmaea and the influence of biotic, abiotic, and anthropogenic factors in shaping their daily and monthly activity patterns in a seasonal tropical forest at the Mexican Pacific slope. Both skunks selected the nocturnal and crepuscular periods, with strong avoidance of daylight hours. We observed partial temporal segregation between species without significant seasonal variation. Spilogale pygmaea was most active when the activity of C. leuconotus decreased, suggesting that S. pygmaea adopts a temporal avoidance strategy to decrease the potential for direct encounters with the dominant species. We found that skunk activity patterns are also determined by the activity of prey and native and exotic predators, as well as relative humidity, precipitation, cloud cover, and night length. Our results showed that these factors differently affect daily and monthly activity between seasons and their effect varies in each species. This study provides evidence that multiple extrinsic factors play an important role in shaping the daily and monthly activity patterns of both skunks and, of course, affect their temporal niche partitioning, possibly promoting coexistence in a seasonal tropical environment.
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